Pedro A. Enríquez

The dynamics of the O(1D)+N2O→NO+NO reaction revisited: a QCT study on model potential energy surfaces

Abstract The dynamics of the O ( 1 D )+ N 2 O → NO + NO reaction has been studied using the quasiclassical trajectory (QCT) method on three different triatomic LEPS (London–Eyring–Polanyi–Sato) potential energy surfaces (PES) model. The NO present in the target N2O molecule has been treated as an atom of 30.0 a.m.u. On the basis of the experimental vibrational distributions and QCT results it is suggested that the NO(v′=16, 17)+NO(v′=0) state-specific reaction channel is not majoritary. However, is about this channel that most of the reaction dynamics information is available. A quite good description of the dynamics of this specific channel has been obtained. We have also shown that for a very exoergic reaction without a strong kinematic constraint, like the one under consideration, the j′=αl angular momenta correlation, with α being a constant, can occur if the PES has no barrier or a negligible one along the minimum energy path and is highly isotropic.

Collision energy effects on the dynamics of the reaction O(3P)+CH4(X1A1)→OH(X2Π)+CH3(X2A2″)

A study of the collision energy effects on the dynamics of the title reaction was performed using the quasi-classical trajectories (QCT) method and an analytical triatomic potential energy surface recently derived by our group. Scalar and two-vector properties of the reaction were analysed in terms of the collision energy. The results obtained can be rationalised in terms of the coexistence of reactive trajectories with rebound and non-rebound features, both corresponding to an abstraction reaction mechanism. Future work should account for both the full dimensionality of the system and the possibility of quantum effects.

Influence of collision energy on the dynamics of the reaction O(1D) + CH4(X1A1) → OH(X 2Π) + CH3(X 2A2″)

We studied the effects of collision energy (ET) on the dynamics of the title reaction using the quasiclassical trajectory method on an analytical triatomic potential energy surface that we had derived for this system. We compared the dependence of the scalar and two-vector properties of the reaction on ET with experimental data and obtained a quite good agreement. The results can be explained in terms of the coexistence of two microscopic reaction mechanisms: insertion and abstraction. The former mechanism is the most important one, although the contribution of the latter increases with ET .

Nascent OH(X2Π) product state distributions from the reaction of O(1D) with ethylene.: A laser-induced fluorescence study

Abstract The full characterization of the OH( X 2 Π , v″=0–3, N″, J″, Λ″) product state distributions for the O ( 1 D )+ C 2 H 4 → OH + C 2 H 3 reaction was experimentally performed using the laser-induced fluorescence (LIF) technique. Statistical spin–orbit distributions were obtained, while some preference for the formation of the Π(A′) Λ-doublet level was observed. The rovibrational populations obtained suggest that the reaction preferentially evolves via insertion, yielding rovibrationally cold OH through slow decomposition of an alcohol-type collision complex and rovibrationally excited OH by fast decomposition. Moreover, some evidences were found about the implication of an abstraction mechanism, which would produce rotationally cold and highly vibrationally excited OH.